1. Field of the Invention
The present invention relates to an apparatus for baking bread and other baked goods, and more particularly, to the apparatus having a dough-surface heating unit a dough-interior heating unit, and a pressure reduction unit for quickly providing freshly baked bread with proper baking color. The present invention also relates to a method for baking bread and other baked good.
2. Description of the Related Art
Center areas and surface areas of baked goods such as breads and cakes have different properties and qualities. Center areas are resilient, although outer areas are stiffer and brittler. Center areas are also moister than the drier surface areas. Both center areas and surface areas are porous, but the pores of center areas are larger and coarser than those of surface areas. The brown color typical of baked goods forms on the surface areas. The process that gives the center and surface areas of breads and cakes these special properties is called baking.
Conventional methods for baking bread and other baked goods usually include baking dough in ovens having a conductive heating unit which heats the dough externally to provide baked goods with the above special properties. There has been known a problem with such conventional ovens in that they require a long time to bake dough because of the low heat conductivity of dough caused by air bubbles contained therein and the drying process involved with baking dough, which takes place in addition to the heating process and is time consuming in conventional ovens. Generally, to bake a roll or similar small baked good in conventional conductive heating ovens (which uses dough-surface heating only) requires 15 minutes whereas to bake a larger item requires 40 minutes or more.
Attempts to increase baking speeds in conventional conductive heating ovens are further frustrated by the need to maintain temperature ranges at the surface of dough required for obtaining good baking color (the appetizing, usually brown, color on surface areas of baked goods which are baked with traditional baking methods). If these temperatures are exceeded in an attempt to quickly bake dough, the end product will be either burned on the outside, unbaked on the inside, or both.
To reduce baking time, there has been known a microwave oven for heating leavened dough to produce such baked goods as breads. The microwave oven heats the interior of dough with microwaves.
Further, there has been proposed a microwave oven which is provided with an electric or gas heating unit.
Another example of prior art related to production of leavened foods is described in Japanese Laid-open Patent S56-23565. This publication discloses heating dough at its interior and subjecting the dough to reduced pressure. However this technique concerns only heating of foods and not baking of foods.
Also, as another example of related art, refer to Japanese Laid-open Patent S56-31933 for information about a manufacturing process for cakes and breads involving reduced cooling by pressure reduction for preventing surface cooling and volume reduction.